Equipped with fresh insights from the fields of cognitive science and psychology, Brian VanDeMark’s Road to Disaster: A New History of America’s Descent Into Vietnam examines how Lyndon Johnson and his Vietnam advisors, “best and the brightest,” as David Halberstam’s famously called them in his seminal work, unspooled the decisions that cost the lives of more than 58,000 Americans. VanDeMark, an associate professor of history at the U.S. Naval Academy, has taught courses on the Vietnam War for nearly 30 years. As a young historian, he assisted Robert McNamara, Lyndon Johnson’s Secretary of Defense, with his controversial 1995 memoir on the war and got to know other senior advisors like Clark Clifford, McNamara’s successor.

After Vietnam, Americans embraced a less jaundiced view of veterans and military service, but VanDeMark also tells The American Prospect that the contemporary polarization that now runs deep in America can be traced back to the stateside backlash against the war. This conversation has been edited and condensed.

Gabrielle Gurley: Support for veterans today is strong, but that wasn’t the case 50 years ago when Vietnam veterans returned home.

Brian VanDeMark: People oftentimes wrestle with why were the people who were sent in harm’s way to do the nation’s work, why were they villainized, ostracized, and criticized rather than the people who sent them? It’s an important thing to remember when our involvement in the war ended and the blame game started, blame got put on shoulders of veterans rather than the decision-makers on Vietnam.

I think the reason is that they lived in our neighborhoods; they were down the street; they were in the bars. But the elites who made the decisions were removed from contact with ordinary Americans. They were insulated from the immediate criticism that was inflicted on veterans.

I got to know many of these senior decision-makers well enough to know that they were also affected by the war. They felt guilt remorse and regret: It’s just that they tended to keep it to themselves. It was generational: You maintain a stoic façade. But what that did is it enabled people to assume that they were either impervious to the consequences of the decisions they made or didn’t regret them. The answer, of course, was that this was not true.

How do you view the polarization of late 1960s compared to the discord today—a period that’s arguably just as polarized?

Vietnam divided the American people deeply and lastingly. A lot of the divisions that exist in American society today between blue and red; left and right; and liberals and conservatives date back to that period. There was a fundamental consensus among the American people on a lot of issues, but Vietnam just destroyed that.

For example, we have deep partisan divisions in the country and a lot of demonization of the other. But in the '60s you had that and marches on the Pentagon, where people were literally physically confronting one another. The state of siege in the country was so severe with Vietnam, the civil rights movement, and urban riots that you had National Guard troops deployed at the Capitol and machine guns with sandbags around the entrances to the House and Senate, which is extraordinary when you think about it in the context of what is happening today.

How do you describe the Vietnam era to your students?

I make it abundantly clear to the students that in addition to every veteran who felt frustrated and angry about decision-making in Washington because they weren’t allowed to “win” the war, you have an equal number of anti-war protestors who were passionately against the war and thought it was unwise to the point of folly.

The middle ground essentially disappeared.

The war tended to drive people away from the center, either in bitter opposition to the war or really passionate advocacy of further military steps. It was very important for my students to understand that the military point of view was real and powerful, but that there were an equal number of Americans who had precisely the opposite interpretation of the war. That wasn’t always a popular thing to do in those classes nearly 30 years ago.

How do they respond?

When I first started teaching there in 1990, I actually taught a course devoted to the Vietnam War exclusively. But you must remember that in those years, the war was still a very recent memory for most Americans. It was so recent in fact that a few of my students in each class were children of fathers who had been killed in the war. It was that close and that personal.

The class was controversial to begin with and when you add that emotional and psychological sensitivity of teaching students who have a very intimate personal relationship to casualties, it was something that really weighed on me. It’s so depressing and so wrenching for a lot of the students to wrestle with. I finally decided to teach Vietnam as part of larger, longer survey history of American involvement in world affairs.

Confronting Vietnam means grappling with the “best and the brightest” conundrum: intelligent men making disastrous decisions. What is it about the psychology of these men that enables us to better understand what happened?

Fifty years ago, people scratched their heads in amazement that smart people could make such stupid decisions. It is a very deep and powerful paradox. Some of it is hubris and ignorance, but I think it goes deeper than that. That’s why I turned to cognitive science and social scientific research in the last 30 or so years.

What kind of cognitive constraints were pronounced in Johnson and his advisors?

I would point to not just Lyndon Johnson, but John F. Kennedy, and Richard Nixon to a greater or lesser degree, as well as to their advisors. They relied on what social scientists refer to as heuristics—simplified rules of thumb that people use to make sense of the world and to process the avalanche of data and impressions that they confront day-to-day when they are wrestling with making decisions.

What a lot of this research demonstrated is that the use of these simplified rules of thumb in complex, stressful conditions can produce very flawed decisions. For example, they were unwilling or unable to constantly re-examine assumptions.

And when we talk about the escalating commitment of troops, which is obviously a very difficult and problematic environment, they fell victim to the sunk-cost fallacy, the tendency on the part of people who have invested in a particular enterprise that doesn’t go well and have an emotional impulse to double down rather than to throw in the towel and walk away.

Human beings, despite their intelligence, are still vulnerable to how they perceive and process information that can produce bad decisions, leading to overconfidence, ignoring essential information, and blindness to your own errors.

Power has a lot of constraints, contradictions, and potential pitfalls that are very real. Vietnam is a cautionary tale about the complexities, dangers, and vulnerabilities that exist at the highest levels of government, where people assume it’s all glory and power.

American policymakers often do not understand that other societies, particularly nonwestern ones, operate very differently than we do. American presidents and their advisors had flawed assumptions about Cuba during the missile crisis, Vietnam, and now Afghanistan. Why is this a difficult lesson for Americans to learn?

The reality of decision-making in Washington is that it is far less "rational actor" in its nature. People at that level very often don’t have the leisure to carefully reflect on assumptions that they are operating on. They have a tendency to affirm a particular set of beliefs that they don’t reexamine. Instead, they keep re-applying them over and over again even though the circumstances that created them may have changed.

All human beings to a greater or lesser degree tend to lock onto information and data that confirm their prejudices and they ignore what does not. That’s not an environment that’s conducive to deep self-reflection and critical introspection.

When you’re a secretary of state or a secretary of defense, you’re not just dealing with Vietnam on a given day or week; you are dealing with multiple problems many of which require decisions immediately. That forces people into hasty and superficial analysis and decision-making and bureaucracies themselves create vulnerabilities for decision makers.

To make matters worse, Johnson did not have a deep reservoir of country experts to draw on inside the government since many of them had been ousted during the communist witch hunts of 1950s.

That’s certainly part of it. In the late 1940s and 50s, a lot of the East Asian specialists in the State Department who had honestly and accurately reported the limitations of the Nationalist government in China and, therefore, drawn the conclusions that the victory of the Communists in the Chinese Civil War was all but inevitable, their careers were destroyed by people like [Senator Joseph] McCarthy and Nixon.

They were essentially forced out of the Foreign Service and their expertise went with them. Those who remained who might have that really gritty, street-level knowledge of a country in that region learned to keep their mouths shut because the consequences of speaking up and speaking candidly would be devastating for their careers.

There were Vietnam experts in the government in the early to mid 1960s when these critical decisions were made to deepen American military involvement. But much of the problem was that they tended to be very far down the bureaucratic food chain and they were often deployed to Vietnam.

The tragedy of LBJ is that he knew the war was a failure but he feared the political consequences of withdrawal.

He feared the consequences of withdrawal even more than he feared the consequences of getting more deeply involved militarily.

In what ways is the stalemate in Afghanistan like Vietnam?

I am not an expert on Afghanistan and as President Obama once put it, there is no perfect historical analogy. But some of the fundamental dynamics are troublingly similar. First, there is the tendency on the part of the United States then as now to believe that the preponderance of military power ought to and will be decisive for its own sake. Second, there is an abiding tendency on the part of the military, to view wars as military problems only. The reality in Afghanistan, as it was in Vietnam, is that wars are profoundly political as well as military in nature and the application of force is not going to address or solve the political dynamics that lie at the root of the problem.

Presidents then and now find, as Clark Clifford once told me, that getting out of a war is a thousand times harder than getting into one. Presidents Obama and Trump both want to get out and the ability to do that is immensely more difficult and complicated than they anticipated, in part, because then as now we are dealing with an ally who is weak and desperately dependent on us and therefore terrified that they’re going to be left to their own devices. Their fear is they are not going to be able to stand face-to-face with their adversary without the Americans being there.

When many Americans think of Vietnam they recall particularly 1968, which was the bloodiest year of the war, but fewer people are familiar with the early 1960s when the war was popular.

When critics hammer the media for their coverage of Vietnam, they always choose the Tet Offensive. They don’t look at how TheNew York Times covered the troop commitments in 1965 and 1966. If you go back and look at that, it’s pretty rah-rah coverage.

Vietnam taught American leaders to keep war out of the news.

Once the draft was abolished in 1973 because of antipathy toward the war, it effectively disconnected military service from the mainstream of American society. Today you have a very professional but very small, separated, and isolated military that essentially fights American’s wars. Main Street doesn’t send its men and women to fight its wars, it’s a small group of men and women who are highly trained and effective but they are invisible to the 99 percent of Americans who have nothing to do with that.

During the Vietnam War, unlike World War II, the U.S. military effectively removed its constraints on the media and let them go wherever and report whatever they wished—and what they reported was what war is really like.

One of the lessons the military drew from that is don’t let that happen anymore. They still allow journalists to accompany them in places like Iraq and Afghanistan but there is much more management about how things are reported.

There is also this myth on the part of many Americans that somehow the media is responsible for America’s defeat in Vietnam, that somehow or another it misreported the war and damaged the American public’s faith in veterans. I disabuse my students of that myth. If you look at how the media reported Vietnam, they reflected public opinion. At the beginning of the war, they were very supportive of the effort.

As the war drags on and American casualties increase, people’s faith in that diminishes. Along with that the media’s coverage of the war becomes incrementally more critical. But it is not a case of them brainwashing the American people. That is a canard. And I definitely want young military officers to grasp that point so they do not demonize the media in a way, which is simply unhistorical and unfair.